#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

#define EVDEV "/dev/input/event0"

// From linux/include/linux/input.h
struct input_event {
	struct timeval time;
	unsigned short type;
	unsigned short code;
	unsigned int value;
};

static inline double doubleTime(const timeval& tv)
{
    return tv.tv_sec + tv.tv_usec / 1000000.0;
}

static const char* typeStr(int evType)
{
    static char buf[16];

    switch (evType) {
    case 0x00: return "RST";
    case 0x01: return "KEY";
    case 0x02: return "REL";
    case 0x03: return "ABS";
    case 0x04: return "MSC";
    case 0x11: return "LED";
    case 0x12: return "SND";
    case 0x14: return "REP";
    case 0x15: return "FF ";
    default:
	sprintf(buf, "%02x ", evType);
	return buf;
    }
}

static const char* keyStr(int key)
{
    static char buf[16];
    switch (key) {
    case 0x110: return "BTN_LEFT   ";
    case 0x111: return "BTN_RIGHT  ";
    case 0x112: return "BTN_MIDDLE ";
    case 0x113: return "BTN_SIDE   ";
    case 0x114: return "BTN_EXTRA  ";
    case 0x115: return "BTN_FORWARD";
    case 0x116: return "BTN_BACK   ";
    default:
	sprintf(buf, "%4x", key);
	return buf;
    }
}

static const char* relStr(int code)
{
    static char buf[16];
    switch (code) {
    case 0x00: return "X     ";
    case 0x01: return "Y     ";
    case 0x02: return "Z     ";
    case 0x06: return "HWHEEL";
    case 0x07: return "DIAL  ";
    case 0x08: return "WHEEL ";
    case 0x09: return "MISC  ";
    default:
	sprintf(buf, "%4x", code);
	return buf;
    }
}

static const char* absStr(int code)
{
    static char buf[16];
    switch (code) {
    case 0x00: return "ABS_X       ";
    case 0x01: return "ABS_Y       ";
    case 0x18: return "ABS_PRESSURE";
    case 0x28: return "ABS_MISC    ";
    default:
	sprintf(buf, "%4x", code);
	return buf;
    }
}

static const char* codeStr(int evType, int code)
{
    static char buf[16];
    switch (evType) {
    case 0x01:				    // KEY
	return keyStr(code);
    case 0x02:				    // REL
	return relStr(code);
    case 0x03:
	return absStr(code);		    // ABS
    default:
	sprintf(buf, "%4x", code);
	return buf;
    }
}

int main(int argc, char* argv[])
{
    const char* devName = EVDEV;
    if (argc > 1)
	devName = argv[1];

    FILE* f = fopen(devName, "r");
    if (!f) {
	fprintf(stderr, "Can't open file %s, errno:%d (%s)\n",
		devName, errno, strerror(errno));
	exit(1);
    }

    input_event ev;

    double t0 = 0;
    while (fread(&ev, sizeof(input_event), 1, f) == 1) {
	if (t0 == 0)
	    t0 = doubleTime(ev.time);
	double t = doubleTime(ev.time) - t0;
	printf("%10f %s %s %4d\n", t, typeStr(ev.type), codeStr(ev.type, ev.code),
	       ev.value);
    }

    fclose(f);
    return 0;
}